The present invention relates to a rotor spinning machine having a plurality of simultaneously operated spinning stations with respective driven spinning rotors, opening rollers, and feed rollers for delivering sliver to the opening rollers.
Generally, in rotor spinning machines, sliver is fed into the opening fixtures at the multiple spinning stations via feed rollers, each of which is connected via worm gear to a common drive shaft extending along the entire spinning machine. In the event of a yarn or sliver break, and during piecing operations, the feed roller is disconnected from the drive shaft via a shiftable coupling. Disadvantageously, connection of the feed rollers to a common drive shaft for driving the feed rollers of the entire machine does not allow individual feeding of the sliver at a spinning station.
For that reason, individual drives of the feed rollers have already been proposed, as known for instance from German patent disclosure DE-OS 34 25 345. However, variable-rpm DC or AC motors as suggested in such reference require expensive control technology in order to establish an individualized speed for a given spinning station rpm.